This invention relates to accessories for drill pointing machines, or machines for sharpening drill bits, and in particular to such accessories which are provided for the purpose of dressing the grinding wheels of such drill pointing machines.
Drill pointing machines as shown in Winslow, U.S. Pat. No. 3,040,480, are generally well known, and are important to machine shops to keep a supply of relatively sharp and properly pointed drill bits on hand. As is also shown in that patent, the grinding wheels used in drill pointing machines as there described tend to wear and lose their proper shape with use, this proper shape being important to proper shaping of the drill point being ground. This loss of shape of the grinding wheel requires a grinding or "dressing" operation to be periodically performed on the wheel to restore it to proper form and shape. Since the drill pointing operation is generally automatic, it is desirable for the dressing operation to be as automatic as possible also.
The Winslow patent shows a dressing apparatus which dresses the grinding wheel according to the shape of a cam, with respect to which a cam follower is moved by a power cylinder. However, in the Winslow apparatus the cylinder moves the cam follower along the surface of the cam, and the dresser tool is held against the wheel solely by the force of a spring. This arrangement can result in less dressing force being applied to the dressing tool and in turn to the wheel. Further, the dressing tool in Winslow is disclosed to be held perpendicular to the axis of rotation of the wheel. In addition, the Winslow patent discloses a dressing apparatus which is designed for application to a specific drill pointing machine.
Montanus, U.S. Pat. No. 3,162,186, shows a dresser apparatus for a grinding wheel including a traverse motor which moves a cam follower along a cam so that a dressing tool is moved both vertically and horizontally. Here again dressing tool is disclosed to be held perpendicular to the axis of rotation of the wheel. In addition the Montanus apparatus is limited as to the wheel shapes it is capable of dressing, requiring that there be smooth curves and no flat vertical faces or reverse angles.
Hoaglund, U.S. Pat. No. 2,938,515 shows a contour forming apparatus which carries a diamond cutting tool at an oblique angle.
This invention relates to improvements to the apparatus described above, to solutions to the problems raised thereby, and to apparatus for other drill pointing machines.